Stockton Complete Bressay Sound Crossing

Stockton Complete Bressay Sound Crossing

Pioneering project demonstrates HDD potential

In July 2016 Stockton Drilling completed the installation of an 11kva cable beneath the Bressay Sound as part of Scottish and Southern Electricity Networks’ Lerwick to Bressay submarine cablerepair project.

Stockton mobilised to Gremista at the Port of Lerwick in the Shetland Isles with their 250t HDD drill spread to install a 500 meter pilot bore within a Sandstone formation to the neighbouring island of Bressay.

The pilot was progressed utilising an 8½” drill motor with a 12 ¼” TCI Drill bit. In order to ensure that the bore followed the planned drill profile, a gyro steering tool was installed within the drilling assembly so that the bore alignment could be tracked at all times across the Bressay Sound to an exit point located only 50 meters landward of the foreshore.

Following the completion of the pilot bore, a 180mm SDR 11 HDPE butt-fusion welded string was pulled back through the bore with lower than projected pull forces.

The 11KVA electrical cable was installed by winch into the HDPE conduit via a preinstalled draw wire.

The project was completed on time, within budget to the high expectations of the client and without impact to Shetland’s unique environment.

Following completion, Project Manager Adam Bain said: This project was a first for Scottish and Southern Electricity Networks and has demonstrated that HDD cable installation can play a part in meeting the future needs of our island customers.

I am extremely happy with the professionalism, commitment and drive that Stockton Drilling showed throughout the works.

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